Slow cookers (better known as Crock-Pots, a name trademarked by the Rival company) may be the only modern kitchen convenience that saves the cook time by using more of it rather than less. And part of their appeal has always been price. But as slow cookers have gained popularity in recent years, manufacturers have added new features-and larger price tags. Does more money buy a better slow cooker? To find out, we rounded up seven models priced between $40 and $150 and put them through some very slow tests in the kitchen.

Time, however, is not really the name of this game. It turns out that what matters is size, at least with our pot roast recipe. We recommend buying a slow cooker with a minimum capacity of 6 quarts. Anything smaller and a modest 5-pound roast, pork loin, or brisket won't fit.

Shape also matters. We found the round crock styles to be deeper than the oval crocks, and they heated more evenly. That said, while the depth and shape of these round cookers made them perfect for submerging a roast in braising liquid, it proved a hindrance with recipes requiring bulky, layered ingredients, such as chicken parts or ribs. Oval-shaped slow cookers have more surface area for cooking and are better suited to these kinds of recipes. Because oval cookers also work when making chilis, stews, or roasts, they are the more versatile choice. However, if you're going to use your slow cooker only for stews and chilis, a round cooker is a possible option.

In addition to differences in size and shape, we noted a variety of features on slow cookers, some of which are quite helpful. A "keep warm" setting is sensible (it turns the heat down once the food is done), but only when paired with a timer. This way, if you are late getting home from work, dinner will still be fine. Without a timer, the keep warm function seems useless. We also liked models with power light—without one, it's hard to tell if the slow cooker is on. As might be expected, a dishwasher-safe crock and lid are desirable. Other features we found beneficial were insert handles (which make it easy to remove the hot insert), and a clear lid that allows you to see the food as it cooks.

One new feature proved less desirable. Two of our models claimed to have stovetop-safe inserts that could be used to first brown the meat and then put directly into the slow cooker. We found, though, that neither insert browned meat very well—the recommended maximum medium heat simply doesn't get the job done. To give this option a final test, we tested a $250 model that had an aluminum pan insert that could take the higher heat. Frankly, we still found the job messy. You still have to cook food in batches for big recipes (which means dirtying another bowl) and pouring off excess fat was a bother. We’d still rather buy a cheaper slow cooker and use a separate skillet for stovetop cooking.

See the Results